// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_SMOOTH_MOVE_GESTURE_H_
#define CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_SMOOTH_MOVE_GESTURE_H_

#include <vector>

#include "base/macros.h"
#include "base/time/time.h"
#include "content/browser/renderer_host/input/synthetic_gesture.h"
#include "content/browser/renderer_host/input/synthetic_gesture_target.h"
#include "content/browser/renderer_host/input/synthetic_pointer_driver.h"
#include "content/common/content_export.h"
#include "content/common/input/synthetic_smooth_drag_gesture_params.h"
#include "content/common/input/synthetic_smooth_scroll_gesture_params.h"
#include "third_party/WebKit/public/platform/WebInputEvent.h"
#include "ui/gfx/geometry/vector2d.h"
#include "ui/gfx/geometry/vector2d_f.h"

namespace content {

class CONTENT_EXPORT SyntheticSmoothMoveGestureParams {
public:
    SyntheticSmoothMoveGestureParams();
    SyntheticSmoothMoveGestureParams(
        const SyntheticSmoothMoveGestureParams& other);
    ~SyntheticSmoothMoveGestureParams();

    enum InputType { MOUSE_DRAG_INPUT,
        MOUSE_WHEEL_INPUT,
        TOUCH_INPUT };

    InputType input_type;
    gfx::PointF start_point;
    std::vector<gfx::Vector2dF> distances;
    int speed_in_pixels_s;
    bool prevent_fling;
    bool add_slop;
};

// This class is used as helper class for simulation of scroll and drag.
// Simulates scrolling/dragging given a sequence of distances as a continuous
// gestures (i.e. when synthesizing touch or mouse drag events, the pointer is
// not lifted when changing scroll direction).
// If no distance is provided or the first one is 0, no touch events are
// generated.
// When synthesizing touch events for scrolling, the first distance is extended
// to compensate for the touch slop.
class CONTENT_EXPORT SyntheticSmoothMoveGesture : public SyntheticGesture {
public:
    explicit SyntheticSmoothMoveGesture(SyntheticSmoothMoveGestureParams params);
    ~SyntheticSmoothMoveGesture() override;

    // SyntheticGesture implementation:
    SyntheticGesture::Result ForwardInputEvents(
        const base::TimeTicks& timestamp,
        SyntheticGestureTarget* target) override;

private:
    enum GestureState {
        SETUP,
        STARTED,
        MOVING,
        STOPPING,
        DONE
    };

    void ForwardTouchInputEvents(
        const base::TimeTicks& timestamp, SyntheticGestureTarget* target);
    void ForwardMouseWheelInputEvents(
        const base::TimeTicks& timestamp, SyntheticGestureTarget* target);
    void ForwardMouseClickInputEvents(
        const base::TimeTicks& timestamp, SyntheticGestureTarget* target);

    void ForwardMouseWheelEvent(SyntheticGestureTarget* target,
        const gfx::Vector2dF& delta,
        const base::TimeTicks& timestamp) const;

    void PressPoint(SyntheticGestureTarget* target,
        const base::TimeTicks& timestamp);
    void MovePoint(SyntheticGestureTarget* target,
        const gfx::Vector2dF& delta,
        const base::TimeTicks& timestamp);
    void ReleasePoint(SyntheticGestureTarget* target,
        const base::TimeTicks& timestamp);

    void AddTouchSlopToFirstDistance(SyntheticGestureTarget* target);
    gfx::Vector2dF GetPositionDeltaAtTime(const base::TimeTicks& timestamp) const;
    void ComputeNextMoveSegment();
    base::TimeTicks ClampTimestamp(const base::TimeTicks& timestamp) const;
    bool FinishedCurrentMoveSegment(const base::TimeTicks& timestamp) const;
    bool IsLastMoveSegment() const;
    bool MoveIsNoOp() const;

    SyntheticSmoothMoveGestureParams params_;
    std::unique_ptr<SyntheticPointerDriver> synthetic_pointer_driver_;
    // Used for mouse input.
    gfx::Vector2d current_move_segment_total_delta_discrete_;
    // Used for touch input.
    gfx::PointF current_move_segment_start_position_;
    GestureState state_;
    int current_move_segment_;
    base::TimeTicks current_move_segment_start_time_;
    base::TimeTicks current_move_segment_stop_time_;

    DISALLOW_COPY_AND_ASSIGN(SyntheticSmoothMoveGesture);
};

} // namespace content

#endif // CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_SMOOTH_MOVE_GESTURE_H_
